/*
 * Copyright (c) 2001-2004 Caucho Technology, Inc.  All rights reserved.
 *
 * The Apache Software License, Version 1.1
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution, if
 *    any, must include the following acknowlegement:
 *       "This product includes software developed by the
 *        Caucho Technology (http://www.caucho.com/)."
 *    Alternately, this acknowlegement may appear in the software itself,
 *    if and wherever such third-party acknowlegements normally appear.
 *
 * 4. The names "Burlap", "Resin", and "Caucho" must not be used to
 *    endorse or promote products derived from this software without prior
 *    written permission. For written permission, please contact
 *    info@caucho.com.
 *
 * 5. Products derived from this software may not be called "Resin"
 *    nor may "Resin" appear in their names without prior written
 *    permission of Caucho Technology.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL CAUCHO TECHNOLOGY OR ITS CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
 * OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
 * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
 * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN
 * IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * @author Scott Ferguson
 */

package com.caucho.hessian.io;

import java.io.IOException;
import java.io.InputStream;
import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.util.ArrayList;
import java.util.HashMap;

/**
 * Input stream for Hessian requests, deserializing objects using the
 * java.io.Serialization protocol.
 *
 * <p>
 * HessianSerializerInput is unbuffered, so any client needs to provide its own
 * buffering.
 *
 * <h3>Serialization</h3>
 *
 * <pre>
 * InputStream is = new FileInputStream("test.xml");
 * HessianOutput in = new HessianSerializerOutput(is);
 *
 * Object obj = in.readObject();
 * is.close();
 * </pre>
 *
 * <h3>Parsing a Hessian reply</h3>
 *
 * <pre>
 * InputStream is = ...; // from http connection
 * HessianInput in = new HessianSerializerInput(is);
 * String value;
 *
 * in.startReply();         // read reply header
 * value = in.readString(); // read string value
 * in.completeReply();      // read reply footer
 * </pre>
 */
public class HessianSerializerInput extends Hessian2Input {
	/**
	 * Creates a new Hessian input stream, initialized with an underlying input
	 * stream.
	 *
	 * @param is
	 *            the underlying input stream.
	 */
	public HessianSerializerInput(InputStream is) {
		super(is);
	}

	/**
	 * Creates an uninitialized Hessian input stream.
	 */
	public HessianSerializerInput() {
		super(null);
	}

	/**
	 * Reads an object from the input stream. cl is known not to be a Map.
	 */
	protected Object readObjectImpl(Class cl) throws IOException {
		try {
			Object obj = cl.newInstance();

			if (_refs == null)
				_refs = new ArrayList();
			_refs.add(obj);

			HashMap fieldMap = getFieldMap(cl);

			int code = read();
			for (; code >= 0 && code != 'z'; code = read()) {
				unread();

				Object key = readObject();

				Field field = (Field) fieldMap.get(key);

				if (field != null) {
					Object value = readObject(field.getType());
					field.set(obj, value);
				} else {
					Object value = readObject();
				}
			}

			if (code != 'z')
				throw expect("map", code);

			// if there's a readResolve method, call it
			try {
				Method method = cl.getMethod("readResolve", new Class[0]);
				return method.invoke(obj, new Object[0]);
			} catch (Exception e) {
			}

			return obj;
		} catch (IOException e) {
			throw e;
		} catch (Exception e) {
			throw new IOExceptionWrapper(e);
		}
	}

	/**
	 * Creates a map of the classes fields.
	 */
	protected HashMap getFieldMap(Class cl) {
		HashMap fieldMap = new HashMap();

		for (; cl != null; cl = cl.getSuperclass()) {
			Field[] fields = cl.getDeclaredFields();
			for (int i = 0; i < fields.length; i++) {
				Field field = fields[i];

				if (Modifier.isTransient(field.getModifiers())
						|| Modifier.isStatic(field.getModifiers()))
					continue;

				// XXX: could parameterize the handler to only deal with public
				field.setAccessible(true);

				fieldMap.put(field.getName(), field);
			}
		}

		return fieldMap;
	}
}
